From: Jaehyun Chung <jaehyun.chung@xxxxxxx> [ Upstream commit 785908cf19c9eb4803f6bf9c0a7447dc3661d5c3 ] [Why] Underflow occurs on some display setups(repro'd on 3x4K HDR) on boot, mode set, and hot-plugs with. Underflow occurs because mem clk is not set high after disabling pstate switching. This behaviour occurs because some calculations assumed displays were synchronized. [How] Add a condition to check if timing sync is disabled so that synchronized vblank can be set to false. Signed-off-by: Jaehyun Chung <jaehyun.chung@xxxxxxx> Reviewed-by: Alvin Lee <Alvin.Lee2@xxxxxxx> Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@xxxxxxx> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c index 6b2f2f1a1c9ce..3980c7b782599 100644 --- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c +++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c @@ -1765,7 +1765,7 @@ int dcn20_populate_dml_pipes_from_context( pipe_cnt = i; continue; } - if (!resource_are_streams_timing_synchronizable( + if (dc->debug.disable_timing_sync || !resource_are_streams_timing_synchronizable( res_ctx->pipe_ctx[pipe_cnt].stream, res_ctx->pipe_ctx[i].stream)) { synchronized_vblank = false; -- 2.20.1